Fan Motors And Drives; Junction Box Condensate Prevention; Motor Power Wiring; Sheaves - Carrier Aero 39MN Series Installation, Start-Up And Service Instructions Manual

Table 30 — Belt Drive Plenum Fan Dimensions
39M UNIT SIZE
FAN
WHEEL
SUPPLY RETURN
123 03W
153 06W,08W 06W,08W
163 08W
183Q 10W
12W,14W, 12W,14W,
223Q
17W
243Q 17W,21W 17W,21W
273Q 21W,25W 21W,25W
303Q 25W,30W 25W,30W
30W,36W, 30W,36W,
333Q
40W
36W,40W, 36W,40W,
363Q
50W
403Q —
50W,61W
443Q 61W 50W,61W
493Q —
40 72W
44 72W,85W 72W,85W
85W,96W, 85W,96W,
49
110W
55 110W
Table 31 — Direct Drive Plenum Fan
Dimensions (in.)
FAN
39M UNIT SIZES
WHEEL
105 03W
122 03W
135 06W
150 06W,08W
165 06W,08W
182 08W,10W,12W
200 10W,12W,14W,16T
12W,14W,16T,17W,
222
18T
14W,16T,17W,18T,
245
21W,22T,25T
17W,21W,22T,25W,
270 25T,27T,30W,30T,
35T
21W,22T,25W,25T,
300
30T,36W,37T
25W,30W,30T,35T,
330
40W
30W,35T,36W,37T,
365
40W,50W,61W
36W,37T,40W,50W,
402
61W
Fan Motors and Drives —
the field, locate the electrical junction box toward the center of
the unit. This arrangement is required for correct belt tension.
Use the smallest mounting holes in the mounting base that will
accommodate the motor and provide minimum overhang.
Tighten the motor holddown bolts. Refer to Table 6 for fan
scroll inlet cone dimensions.
JUNCTION BOX CONDENSATE PREVENTION —
When air handlers are installed outdoors in a high humidity
environment or indoors where the apparatus room is used as
(in.)
LENGTH WIDTH HEIGHT
03W 41.0 23.4
42.5 36.0
08W 24.8 46.5
10W 26.3 53.3
29.6 58.3
17W
32.6 62.5
36.5 66.3
38.8 70.3
41.0 75.8
40W
48.9 91.4
50W
40W 48.9 91.4
50W 57.4 99.4
57.4 99.4
61W 57.4 99.4
72W 34.2 92.2
38.0 100.0
41.3 107.8
110W
110W 52.3 114.7
FAN SLED ASSEMBLY
LENGTH WIDTH HEIGHT
21.0 19.4 18.2
22.5 21.6 20.2
23.6 22.7 21.0
27.0 25.4 22.9
27.8 27.0 24.5
31.1 29.1 26.8
32.8 31.5 29.5
36.3 34.6 32.0
37.8 37.4 34.9
40.6 41.0 34.7
46.6 44.7 40.9
48.4 47.9 43.5
51.8 51.4 46.7
54.8 52.3 53.6
When installing motors in
a fresh air plenum, precautions must be taken to prevent
condensation from forming inside the junction box of the
internally mounted motor.
Standard installation practice is to mount the motor starter
or fused disconnect box adjacent to the air handler and enclose
23.7
the power wiring to the motor in flexible conduit.
26.2
The sheet metal housing of the disconnect switch or motor
29.1
starter is not airtight (even when a box meeting NEMA [Na-
31.3
tional Electrical Manufacturers Association] IV standards is
used). Thus, warm moist air can migrate through the flexible
36.7
conduit to the junction box on the motor. With the motor locat-
40.1
ed inside the unit, the motor temperature is that of the cool sup-
41.4 ply air, so condensate can form inside the junction box and,
possibly, on the live terminal lugs.
45.4
To prevent the moist air from migrating through the conduit
48.9
to the motor, seal the power wires inside the flexible conduit at
the motor starter or fused disconnect (Fig. 45).
54.4
Use a nonconductive, non-hardening sealant. Permagum
58.3
(manufactured by Schnee Morehead) or sealing compound,
58.4
thumb grade (manufactured by Calgon), are acceptable
64.0
materials.
70.0
56.4
61.4
68.9
76.4
Fig. 45 — Sealing Power Wires in Flexible Conduit
Motor Power Wiring —
with a decal indicating the recommended location to drill or
punch hole(s) to accommodate an electrical conduit for the
fan-motor wiring. The decal is located on the motor side,
approximately 4 in. in from the side and 4 in. down from
the top of the corner above where the motor will be
installed. Where possible, the conduit should be installed in
a panel which will not be removed, such as the discharge
panel.
MOTOR OVERLOAD PROTECTION — Fan-motor start-
ers and overload protectors are field-supplied and installed. A
label on the fan motor indicates the correct size of the overload
protectors required to be installed in the motor starter.
Sheaves —
tensioned. However, Carrier recommends checking the belt
tension and alignment before starting the unit. Always check
the drive alignment after adjusting belt tension.
To install sheaves on the fan or motor shaft, remove any
rust-preventive coating on the shaft. Make sure the shaft is
clean and free of burrs. Add grease or lubricant to bore of
sheave before installing. Mount sheave on the shaft; to prevent
bearing damage, do not use excessive force (i.e., a hammer).
Place sheaves for minimum overhang (see Fig. 46).
Each factory-assembled fan, shaft, and drive sheave assem-
bly is precision aligned and balanced. If excessive unit vibra-
tion occurs after field replacement of sheaves, the unit should
be rebalanced. To change the drive ratio, reselect and replace
the motor sheave, not the fan sheave.
After 24 hours of unit operation, the drive belts may stretch.
Check the belt tension after 24 hours of operation and adjust if
necessary. Periodically check belt tension throughout the run-in
period, which is normally the initial 72 hours of operation.
106
The fan section is provided
Factory-supplied drives are pre-aligned and
a39-1108tf